Synthetic growth hormone enables treatment of all children with growth hormone (GH) deficiency, including partial GH deficiency. Poorly growing children with normal responses to standard tests for GH deficiency may be partially deficient and could be treated. A method of evaluating GH function without pharmacologic tests is to determine GH levels at 20 minute intervals during sleep. This project evaluates the growth response to synthetic GH in children growing slowly with normal responses to standard tests but low levels of GH.